The subject matter disclosed herein relates to gas turbine engines and, more particularly, to compressor load management therein.
In a gas turbine engine, air is pressurized in a multistage axial compressor and mixed with fuel in a combustor for generating hot combustion gas that flows downstream through one or more turbine stages for extraction of energy from the gas.
A multistage axial compressor will typically include a series of stationary nozzle assemblies composed of individual compressor stator blades that are supported in mounting slots in the compressor housing. The nozzle assemblies receive air, either ambient at the compressor inlet or compressed air from an upstream compressor stage, and direct it to rotating compressor rotor blades that compress the air for eventual delivery to the combustor, as well as to the turbine for cooling and sealing purposes.
The compressor stator blades may comprise an airfoil and a base, having features that allow the base to be mounted within the housing slots. The compressor housing, being typically defined by two 180-degree segments that assemble to complete the 360-degree housing, receives each stator blade base in the machined slot to thereby define the stationary nozzle assembly. The stator base members may reside in relatively unrestrained end-to-end abutment with one another such that, as air enters and passes through the nozzle assembly, the force of the airflow over the airfoils causes a tangential load on each of the stator bases in a circumferential direction. As a result, the series of stator blades and associated stator blade bases experience a compressive force in a circumferential direction about the 180 degree housing segments resulting in significant compressive force being applied to the stator bases located at the 9 o'clock and 3 o'clock positions within the housing segments. These components recognize the highest compressive loads and, thus, the highest damping versus the stators and associated bases that are positioned 180 degrees away that experience minimal loading and damping. The result of this configuration may be a high degree of vibrational activity from the lightly loaded stator vanes resulting in lower than desirable compressor durability.
It is desirable to provide an axial compressor having a low degree of vibrational activity across the entire nozzle assembly and a consistent force loading of the stator blades thereof.